The ultimate (Phase III) objective of this effort is to fully optimize the electronic and power components of the artificial heart support system to minimize the demands on the battery, and to develop a high energy density zinc-air battery pack, to yield a system that is very light weight and completely portable in order to gain popular patient and public acceptance of the artificial heart. The purpose of this Phase I effort is to: 1) optimize the efficiency of the reversing DC motor, during the period of its reversal, by employing the methods of dynamic braking, coasting and plug reversing with pulse width modulation, to minimize the power required to reverse the pump; and 2) prove the utility of a zinc-air battery pack to provide adequate power at reduced volume and weight. Bench testing will be performed to identify the optimum controller configuration. Then the optimum configuration will be tested using actual battery packs to determine the maximum time of battery use. The battery packs will be constructed using zinc-air button cells which have an energy density twelve times that of high quality nickel-cadmium cells. The present controller configuration will be tested to establish a base-line.